1120 THE VOYAGE OF H.M.S. CHALLENGER. 



The small number of species here enumerated may be easily increased, since numerous 

 forms, belonging probably to this family, are not sufficiently known. Their study is, 

 however, very difficult and requires accurate examination of the tiny shells from different 

 sides. 



The four genera of Pylobotryida, here described, represent two different subfamilies. 

 The terminal mouth of the abdomen remains open in the Botryocyrtida, whilst it 

 becomes closed by a lattice-plate in the Botryocampida. There are in both groups 

 shells with and without porous tubes; the number of these tubes, and also the number 

 and disposition of the lobes in the cephalis, exhibit remarkable differences in the different 

 species of those genera, and may in future serve for their division into a greater number 

 of genera. 



Synopsis of the Genera of Pylobotryida. 



I. Subfamily ( Cephalis witliout porous tubes, . . . 492. Botryocyrtis. 



Botryocyrtida. ■' 



Mouth of the abdomen open. ( Cephalis with a variable number of porous tubes, . 493. Pylohotrys. 



II. Subfamily 



Botryocampida. 

 Mouth of the abdomen closed 

 by a lattice-plate. 



Cephalis without porous tubes, . . . 494. Botryocampe. 



Cephalis with a variable number of porous tubes, . 495. Phormobotrys. 



Genus 492. Botryocyrtis,^ Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. d. 



Wiss. Berlin, p. 829. 



Definition. — P ylobotryida without tubes on the cephalis, and with the mouth 

 of the abdomen open. 



The genus Botryocyrtis, founded by Ehrenberg upon two Indian species, is the 

 simplest among the Pylobotryida. It may have been derived from Botryopyle by the 

 development of an abdomen (or a third shell -joint), the mouth of which remains open. 



1. Botryocyrtis serpentis, Ehrenberg. 



Botryocyrtis serpentis, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 287, Taf. x. 

 fig. 21. 



Cephalis quadrilobate ; the odd frontal and the two paired buccal lobes subspherical, about half 

 as large as the odd occipital lobe. Thorax inflated, about as long as the cephalis and half as long as 

 the ovate abdomen. Mouth of the latter constricted, of half the breadth. 



DimensioTis. — Length of the shell 0'12, breadth 0'06. 



Habitat. — Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen. 



1 £oir2/oci/rtis= Basket with grapes ; ^otjk;, xv^tI;. 



